We know that the one-time pad is provably secure as a cipher to encrypt some data. Is there an algorithm which does the same just as a hash function? Can we get a provably secure hash function? Maybe ...

where $g$ is a group element in bilinear group $\mathbb{G}$. I understand it is very similar to the conventional DBDH problem, but $g^{1/b}$ is also known, possibly making it easier? Does anyone know ...

In the Bernstein et al. paper about EdDSA, the authors claim EdDSA is resilient against collisions (i.e. it can still be secure even if the hash function used isn't collision-resistant), drawing on a ...

Let suppose that we have to check a message that was written one second ago. The message is discarded immediately after having being checked. What "minimal" size for such a MAC is secure ?
Thank you.
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Do you mind if you give me any hints, links or ideas about how to improve the security of double regular encryption and decryption, by using CPA game and CCA game, it sounds interesting question, and ...

We define the polynomials $r, f_1,f_2,s \in R[x]$. Where $r$ is a random degree 1 polynomial and $s$ is a random polynomial such that: $degree(s)=degree(f_1)=degree(f_2)$, let $R$ be $\mathbb{Z}_p$ ...

Does it mean that when PPT attacker is breaking an indistinguishable based (equivalent with semantic security) game with non negligible probability that he is able to infer the secret keys either on ...

I am in the design phase of a secure chat application at the moment. I am trying to make this as secure as possible.
The Serverprovider should not have access to the messagedata.
So my idea was the ...

I've been studying cryptography for a little while. I understand fairly well the nuts and bolts of security proofs, but I'm having trouble reconciling the formal statements of security in these proofs ...

While dabbling in privacy-preserving protocols (mainly using Semi-Homomorphic Encryption) and coming up with miscellaneous ideas for comparison tests or other similar primitives, based on obfuscation ...

CryptDB has Onion layers of Encryption to provide wider functionality from weaker forms of encryption. How do we prove such things are indeed secure ? Intuitively It seems ok. Are there any parallels ...

This paper considers the exponent to be an odd integer.
When k = 2, it is called the quadratic residuosity problem (mod n where n is composite) which is hard and can be solved if the factorization of ...

Say we are able to decrypt a Elgamal ciphertext $c$ using only the public key. Apparantly it is now possible to solve the Diffie-Hellman problem (given $g^a, g^b$ calculate $g^{ab}$). How?
I know how ...

I'm learning the POK notion and definitions and as a self exercise I wante to prove the statement that the Hamiltonicity protocol is a POK system with knowledge error $1/2$.
So the question will be ...

Given, say, the Blowfish block cipher, which is considered secure but only has a 64-bit block size, can we construct a secure block cipher of 128-bit block size?
Say we run the key through two KDFs, ...

I'm looking for a very detailed example of proof by reduction. Say we have two or three protocols (that have been proven secure) and we construct a new protocol. We want to provide a proof of security ...

I'm trying to design cryptographic protocol to play Rock-Paper-Scissors with two parties, neither trusting each other, nor trusting server they use for communication, so game is 'provably fair'.
So ...

One-Time-Pad is information theoretically secure as long as the random number stream is evenly long or longer than the data stream it encrypts, for a "decyphered" message could have been any message ...